Football's lawmakers, the International Football Association Board (IFAB), made three decisions at a special meeting convened at the headquarters of the world body FIFA on Thursday.

One IFAB verdict concerned additional assistant referees following an experiment, in particular in the UEFA Champions League, UEFA Europa League and at UEFA EURO 2012.

The IFAB unanimously agreed that the use of two additional assistant referees be approved, acknowledging the support they can provide in officiating matches. As a result of this decision, an amendment will be made to the Laws of the Game, with a separate section concerning additional assistant referees. It was also approved that communication equipment be permitted between match officials in the Laws of the Game.

With regard to goal-line technology, and following a nine-month testing process, the IFAB unanimously decided to approve in principle both companies that took part in the second test phase: GoalRef and Hawk-Eye. This approval is subject to a final installation test at each stadium before the systems can be used in 'real' football matches.

The IFAB was keen to stress that technology will only be utilised for the goal line and for no other areas of the game. Revisions to the wording of specific Laws of the Game will consequently be made, relating to: Law 1 (The Field of Play), Law 2 (The Ball), Law 5 (The Referee) and Law 10 (The Method of Scoring).

At the meeting, it was also agreed by the IFAB to unanimously approve – temporarily during a trial period – the wearing of headscarves. The design, colour and material permitted will be defined and confirmed following the IFAB annual business meeting in Glasgow in October.

The decisions concerning the Laws of the Game taken today regarding goal-line technology and additional assistant referees by the IFAB will come into effect immediately.